Agitator Design Calculation Software

Agitator Power Equation:

\[ P = N_p \times \rho \times N^3 \times D^5 \]

Power Number (N_p):

unitless

Density (ρ):

kg/m³

Rotational Speed (N):

rev/s

Diameter (D):

Agitator Power (P):

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1. What is Agitator Power Calculation?

Agitator power calculation determines the power required to operate a mixing impeller in a fluid. It is essential for proper agitator design and motor selection in chemical, pharmaceutical, and food processing industries.

2. How Does the Calculator Work?

The calculator uses the agitator power equation:

\[ P = N_p \times \rho \times N^3 \times D^5 \]

Where:

\( P \) — Agitator power (watts)
\( N_p \) — Power number (unitless)
\( \rho \) — Fluid density (kg/m³)
\( N \) — Rotational speed (rev/s)
\( D \) — Impeller diameter (m)

Explanation: The power number depends on impeller type and flow regime (laminar or turbulent). This equation calculates the power required to overcome fluid resistance during mixing.

3. Importance of Agitator Power Calculation

Details: Accurate power calculation ensures proper motor sizing, prevents under-mixing or over-mixing, optimizes energy consumption, and ensures process efficiency and safety.

4. Using the Calculator

Tips: Enter power number based on impeller type, fluid density in kg/m³, rotational speed in revolutions per second, and impeller diameter in meters. All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What is the power number (N_p)?
A: The power number is a dimensionless parameter that characterizes the resistance of an impeller to rotation in a fluid. It varies with impeller type and Reynolds number.

Q2: How do I determine the power number?
A: Power numbers are typically obtained from manufacturer specifications, experimental data, or published correlations for specific impeller types.

Q3: What are typical power number values?
A: Common values range from 0.3 to 6.0 depending on impeller design. For example, marine propellers have lower N_p while Rushton turbines have higher values.

Q4: Does fluid viscosity affect the calculation?
A: Yes, viscosity affects the power number, especially in laminar flow regimes. The power number becomes constant only in fully turbulent flow.

Q5: Can this calculator be used for non-Newtonian fluids?
A: For non-Newtonian fluids, apparent viscosity must be used, and power number correlations become more complex due to shear-dependent viscosity.